Navigation device.



H. S. GIST.

NAVIGATION DEVICE. APPLIOATION FILED NOV. 12, 1913.

1,098,621 Patented June 2, 1914.

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H. S. GIST.

NAVIGATION DEVICE.

APPLICATION FILED NOV. 12, 1913.

Patented June 2, 1914.

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UNITED STATES PATENT OFFICE.

HENRY SAMUEL GIST, OF HENDON, LONDON, ENGLAND.

NAVIGATION DEVICE.

.as will enable others skilled in the art to which it appertains to makeand use the same.

This invention relates to an improved navigation device, which, whiledesigned and primarily intended for navigating aerial craft, is equallyapplicable for marine pur poses. Its object is to provide an immediatemeans of ascertaining a course from point to point on any mapirrespective of whether such map is provided with divided borders orclose latitude and longitude divisions provided that the true'ormagnetic north is indicated.

The invention is carried out as follows reference being madeto theaccompanying drawings in which Figure 1. is a plan of the device. Fig.2. is a section of a modification of same showing details ofconstruction. Fig. 3. shows a section of the device when mounted over aroller map, suitable for attachment to an aeroplane fuselage. Fig. 1.shows detail of N or zero stop on disk. Fig. 5. shows detail of lockingdevice between the compass ring and disk.

In the drawings 1 is the transparent disk made from any suitablematerial such as celluloid, casein, glass or the like. Said disk ismounted so as to be freely rotatable and preferably in a concentriccircumferential bearing 1 so as to give a clear view of the map 2,disposed beneath the disk. The bearing 1 consists of a metalring screwedto the underside of the compass ring, the rabbet being deep enough toallow the material of the disk to expand or contract. The disk 1 isruled with a plurality of fine equi-spaced parallel lines 3, one ofwhich passes through the center of the disk said line being providedwith a pointer as shown at 3*. This line may be of a different color tothe others or it may have the usual N indication. A knob 1 is providedfor rotating said disk.

concentrically mounted with respect to the disk 1 is an annular compassring 4 divided into degrees and the usual compass points. This ring isjournaled peripherally Specification of Letters Patent.

Application filed November 12, 1913.

Serial No. 800,490.

in a seating 4 a brass or like ring l" retalnmg same in position soas tobe capable of rotation, and above this ring, and circumferentiallymounted therewith in a state of fixity is a magnetic variation device 5preferably divided with divisions that are radial extensions of thecompass ring divi- SlOIlS.

The compass ring 4.- is at one point provided with a handle 6, by meansof which the compass ring may be rotated. A looking device is providedbetween the compass ring and the disk, and one method of carrying thisout is shown in Fig. 5, in which the disk bearing ring l is slotted anda pivoted clip 7 provided that is tensioned by a screw 8 and normallyheld in an inoperative position by spring 9. By these means the disk 1may be locked to the compass ring 4 and the two rotated together. Asimilar locking device is provided for the compass ring for the purposeof locking this ring only. This consists of a spring 10 pivoted at 10*having a handle 10 and moving radially over the metal plate 10 saidplate having a stop 10. The lock in this case is frictional and issuflicient for the purpose. The wholeof these devices are mounted andjournaled in a suitable seating or frame A, capable of being disposedabove the map 2, or if the map is of the strip and roller variety,(which are much used for aviation purposes) they may be mounted upon thelid of a box 12 containing the map rollers as shown in Fig. 3, the boXhaving external handles 13 for moving the map as shown in Fig. 1.

One method of operating this invention is as follows :The central diskand compass ring are locked together by means of the screw 8 with theirN indications coinciding with each other and with the zero of thevariation indicator disposed'over the chart, they are then rotated untilthe ruled lines on the disk are parallel to the north line indication onthe chart. The compass ring is now locked and the disk is released androtated by it-self until the ruled lines are parallel to the coursedesired from point to point, when the number of degrees to be steeredeast or west of N will be found indicated on the compass ring coincidentwith the disk pointer. The disk and ring may now be locked together bymeans of the screw 8. To facilitate reading the compass ring may beprovided with two scales reading right and left from the north point.

Patented June 2, 1914.

To allow for ma netic variation the comb 7 pass ring and disk, whenlocked together are moved east or west accordlng to the variationlnvariably marked on every navigation chart, the ring being set by thedivisions on the variation indicator 5. The device now gives the courseto be steered by compass with extreme accuracy leaving only currents orwindage to be allowed for.

F or marine or dirigible purposes the whole compass ring and disk may bemounted upon a board and so arranged that it can be moved over astationary map and the course read off as described, this type is shownin section in Fig. 2. For such purposes the disk 1 may be slotted asshown at 14:, the sides of the slots being used for marking the desiredcourse upon the chart prior to the use of the device for its functionalpurposes.

In order that the N point between the compass ring i and the disk 1, maybe readily found, the fit between the bearing of the disk and the diskitself may be such that suflicient play is given to the disk that it iscapable of depression against a spring 15 and be engaged or disengagedfrom the pro jection 16, on the underside of the ring (it. The diskhaving a hole or depression 17 that engages said projection.

I claim.

1. In a navigation device, the combination, with a supporting frameprovided with an opening, of a graduated compass ring and a markedtranslucent disk mounted in the said opening and revoluble thereinindependently of each other, means for locking the compass ring and disktogether, and means for locking the compass ring to the frame.

2. In a navigation device, the combination, with a supporting frameprovided with an opening, of a graduated compass ring and a markedtranslucent disk mounted in the said opening and revoluble thereininclependently of each other, a magnetic variation scale arrangedadjacent to and concentric with the compass ring, means for looking thecompass ring and disk together, and means for locking the compass ringto the frame.

3. In a navigation device, the combination, with a supporting frameprovided with an opening, of a graduated compass ring and a markedtranslucent disk mounted in the said opening and revoluble thereinindependently of each other, a spring-released locking-clip pivotallysupported from the compass ring, a screw engaging with a screwthreadedhole in the compass ring and oper ating to press the locking-clipagainst the said disk, and means for locking the compass disk to theframe.

In testimony whereof I have affixed my signature, in presence of twowitnesses.

HENRY SAMUEL GIST. @Vitnesses O. J. Woarnt, L. E. Bowln.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. G.

